Dissolution-Accompanied Aggregation Kinetics of Silver Nanoparticles
Dissolution-Accompanied Aggregation Kinetics of Silver Nanoparticles
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DOI：
10.1021/la101768n
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发表时间：
2010-11-16
期刊：
影响因子：
3.9
通讯作者：
Walker, Harold W.
中科院分区：
文献类型：
--
作者：
Li, Xuan;Lenhart, John J.;Walker, Harold W.
通过与d -麦芽糖还原Ag(NH3)(2)（+）配合物，合成了直径为82 +/- 1.3 nm的裸银纳米颗粒，并对其形貌、晶体结构进行了表征。测定了紫外-可见光谱和电泳迁移率。动态光散射通过测量不同电解质类型（NaCl、NaNO3和CaCl2）和浓度下纳米颗粒的平均水动力直径随时间的变化来评估早期聚集动力学。由此确定了临界凝血浓度为30,40。NaNO3、NaCl和CaCl2分别为2 mM。虽然观察到银纳米颗粒在所有三种电解质溶液中溶解，但聚集结果仍然符合经典的Derjaguin-Landau-Verwey-Overbeek （DLVO）理论。银纳米粒子表面包裹一层Ag2O，其溶解程度与电解质类型和浓度密切相关。在含Cl-的体系中，次级沉淀（可能是AgCl）也会形成并形成一层包含银纳米粒子的涂层。在北欧水生黄腐酸存在的情况下，银纳米粒子的聚集也被检查，与在相同的无黄腐酸条件下的评估相比，几乎没有变化。这些结果为进一步研究银纳米粒子在天然水生系统中的环境命运提供了基础。
Bare silver nanoparticles with diameters of 82 +/- 1.3 nm were synthesized by the reduction of the Ag(NH3)(2)(+) complex with D-maltose, and their morphology, crystalline structure. UV-vis spectrum, and electrophoretic mobilities were determined. Dynamic light scattering was employed to assess early stage aggregation kinetics by measuring the change in the average hydrodynamic diameter of the nanoparticles with time over a range of electrolyte types (NaCl, NaNO3, and CaCl2) and concentrations. From this the critical coagulation concentration values were identified as 30, 40. and 2 mM for NaNO3, NaCl, and CaCl2, respectively. Although the silver nanoparticles were observed to dissolve in all three electrolyte solutions, the aggregation results were still consistent with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The dissolution or the silver nanoparticles, which were coated with a layer or Ag2O, was highly dependent on the electrolyte type and concentration. In systems with Cl- a secondary precipitate, likely AgCl, also formed and produced a coating layer that incorporated the silver nanoparticles. Aggregation of the silver nanoparticles was also examined in the presence of Nordic aquatic fulvic acid and was little changed compared to that evaluated under identical fulvic acid-Free conditions. These results provide a fundamental basis for further studies evaluating the environmental fate of silver nanoparticles in natural aquatic systems.